Originally posted by KneverKnightYes but the surface of a sphere does have limits - it's area is limited. It's easy to measure it's limits. Not so for the universe. Until we can determine it's limits, then as far as we can tell, it's an open system.
The universe could be finite yet have no boundaries, something like the surface of a sphere does in a two-dimensional sense ie you can orbit the earth as much as you want without running into a wall yet the area of the Earth's surface is finite.
If there were beings who knew only two dimensions, they would be puzzled to set off one day due East and fin ...[text shortened]... wo-dimensional travellers might deduce the existence of a third dimension from this experience.
Originally posted by ColettiMan, you just fell into your own logical trap mate. If the universe is infinite there can be nothing else. There cannot be anything else 'outside' the universe. The universe must be closed by definition.
The point is you can not delineate the boundary of the what you assume to be the "ultimate closed system." How do you close an infinite system? It's just speculation that the universe is a closed system - and very unscientific.
For reference for you, from Wiki;
Universe - All matter and energy, including the earth, the galaxies, and the contents of intergalactic space, regarded as a whole.
Originally posted by The Chess ExpressIf nothing exists then what you have is a vacuum. If there is a vacuum, then the universe would have to lose light and heat into it every time it cycles through expanding and contracting.
A universe that cycles through expanding and collapsing would not exist forever because it would loose heat and light through every cycle.
[b]What? Where does it lose that energy to? Where did you get this idea?
If nothing exists then what you have is a vacuum. If there is a vacuum, then the universe would have to lose light and heat into it every time it cycles through expanding and contracting.[/b]
This makes no sense. If you have an empty glass, and you pour water in, the water doesn't disappear. According to your logic it does!
Originally posted by ColettiWell, according to some string theories, there could be as many as 11 dimensions, but that's not quite what I meant.(The extra dimensions remained curled up as spacetime expanded during the inflationary period following the Big Bang)
Yes but the surface of a sphere does have limits - it's area is limited. It's easy to measure it's limits. Not so for the universe. Until we can determine it's limits, then as far as we can tell, it's an open system.
If it were possible to shoot off a ray of light in a certain direction, wait (possibly a VERY long time) and have the same ray arrive back at the origin would entail (perhaps) the light travelling around the universe, unbounded yet traversing some finite distance, through another dimension, to arrive back at the origin.
In this way, the universe could be unbounded yet finite.
It's hard to visualize because we can only see 3 dimensions (and measure 4) We imagine setting off in a rocket and after some time, arriving at a wall which has a sign saying "The End Of The Universe", and wondering what is behind the wall.
Doesn't mean there aren't other dimensions which can turn us around and send us back without ever meeting any wall.
Let's imagine some early time when the universe was 1cm in radius. (Which may or may not make this idea clearer ...)
IF, anything sent out in a certain direction always returned to the point of origin, the answer to asking what is "outside" is maybe meaningless or just undefined.
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Originally posted by scottishinnzThere are many different kinds of infinities. If you draw two lines on a sheet of paper, both have an infinite number of points. There can be as many infinities as you like, and there can still be stuff outside of them.
Man, you just fell into your own logical trap mate. If the universe is infinite there can be nothing else. There cannot be anything else 'outside' the universe. The universe must be closed by definition.
For reference for you, from Wiki;
Universe - All matter and energy, including the earth, the galaxies, and the contents of intergalactic space, regarded as a whole.
Originally posted by scottishinnzYour analogy is way off. I’m not sure how you got it. If you have an empty space, then nothing exists in it. An empty space can be filled with something. The universe would loose light and heat into the empty space with every cycle.
If nothing exists then what you have is a vacuum. If there is a vacuum, then the universe would have to lose light and heat into it every time it cycles through expanding and contracting.
This makes no sense. If you have an empty glass, and you pour water in, the water doesn't disappear. According to your logic it does!
Originally posted by The Chess ExpressOkay, but a line has an infinite number of points. The universe is infinite in that it contains everything.
There are many different kinds of infinities. If you draw two lines on a sheet of paper, both have an infinite number of points. There can be as many infinities as you like, and there can still be stuff outside of it.
Originally posted by The Chess ExpressBut it still exists within the universe. You cannot destroy either heat or light. Anyhoo, heat is simply the movement of atoms. If you have a perfect vacuum you have no atoms, and therefore no heat. You can only have heat once there is something in it, in which case it's no longer a perfect vacuum.
Your analogy is way off. I’m not sure how you got it. If you have an empty space, then nothing exists in it. An empty space can be filled with something. The universe would loose light and heat into the empty space with every cycle.
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Originally posted by scottishinnzIt only contains everything that we know. Do you think we know everything? Other universes could contain more things.
Okay, but a line has an infinite number of points. The universe is infinite in that it contains everything.
If everything that you know is represented by the infinite number of points on a line, that doesn't mean that there aren't other lines (universes) out there.
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Originally posted by scottishinnzAs a scientist you accept the physical right? That is the universe is simply made up of matter. If all the matter gets condensed into a singularity, that would give off an unimaginable amount of energy. That energy would be lost in the vacuum. In this way all the matter of the universe would eventually be lost as energy in the form of light and heat.
But it still exists within the universe. You cannot destroy either heat or light. Anyhoo, heat is simply the movement of atoms. If you have a perfect vacuum you have no atoms, and therefore no heat. You can only have heat once there is something in it, in which case it's no longer a perfect vacuum.
Originally posted by The Chess ExpressNope. A singularity would have infinite gravity. Nothing, no heat (because that, as explained, requires atoms to escape), no light, nothing.
As a scientist you accept the physical right? That is the universe is simple made up of matter. If all the matter gets condensed into a singularity, that would give off an unimaginable amount of energy. That energy would be lost in the vacuum. In this way all the matter of the universe would eventually be lost as energy in the form of light and heat.
Originally posted by scottishinnzIf that’s true then we wouldn’t have any matter left. All we would have is heat and light. According to science heat and light don’t mix to create something physical.
Nope. A singularity would have infinite gravity. Nothing, no heat (because that, as explained, requires atoms to escape), no light, nothing.
Originally posted by The Chess ExpressBull.
If that’s true then we wouldn’t have any matter left. All we would have is heat and light. According to science heat and light don’t mix to create something physical.
Thermodynamics means that yes, eventually the universe will tend towards heat and light. Both of those, of course are forms of energy, and the last time I looked E=MC^2. The universe will come to an equilibruim, that's all.
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Originally posted by scottishinnzThat is a great argument that the universe is not eternal! If it were eternal, the universe would have become heat and light an eternity ago as I said.
Bull.
Thermodynamics means that yes, eventually the universe will tend towards heat and light. Both of those, of course are forms of energy, and the last time I looked E=MC^2. The universe will come to an equilibruim, that's all.
Originally posted by scottishinnzEntropy, or, the arguement for housework.
Bull.
Thermodynamics means that yes, eventually the universe will tend towards heat and light. Both of those, of course are forms of energy, and the last time I looked E=MC^2. The universe will come to an equilibruim, that's all.